The role of exotic plants in the invasion of Seychelles by the polyphagous insect Aleurodicus disperses: a phylogenetically controlled analysis

The accidental introduction of the spiralling whitefly, Aleurodicus dispersus Russell (Homoptera: Aleyrodidae) to Seychelles in late 2003 is exploited during early 2005 to study interactions between A. dispersus, native and exotic host plants and their associated arthropod fauna. The numbers of A. dispersus egg spirals and pupae, predator and herbivore taxa were recorded for eight related native/exotic pairs of host plants found on Mahe, the largest island in Seychelles. Our data revealed no significant difference in herbivore density (excluding A. dispersus) between related native and exotic plants, which suggests that the exotic plants do not benefit from 'enemy release'. There were also no differences in predator density, or combined species richness between native and exotic plants. Together these data suggest that 'biotic resistance' to invasion is also unlikely. Despite the apparent lack of differences in community structure significantly fewer A. dispersus egg spirals and pupae were found on the native plants than on the exotic plants. Additional data on A. dispersus density were collected on Cousin Island, a managed nature reserve in which exotic plants are carefully controlled. Significantly higher densities of A. dispersus were observed on Mahe, where exotic plants are abundant, than on Cousin. These data suggest that the rapid invasion of Seychelles by A. dispersus may largely be due to the high proportion of plant species that are both exotic and hosts of A. dispersus; no support was found for either the 'enemy release' or the 'biotic resistance' hypotheses.

Seasonal 'fall out' of sessile macro-fauna from submarine cliffs: quantification, causes and implications

Submarine cliffs are typically crowded with sessile organisms, most of which are ultimately exported downwards. Here we report a 24 month study of benthic fauna dropping from such cliffs at sites of differing cliff angle and flow rates at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The magnitude of 'fall out' material collected in capture nets was highly seasonal and composed of sessile and mobile elements. Sponges, ascidians, cnidarians, polychaetes, bryozoans and barnacles dominated the sessile forms. The remainder (mobile fauna) were scavengers and predators such as asteroid echinoderms, gastropod molluscs and malacostracan crustaceans. These were probably migrants targeting fallen sessile organisms. 'Fall out' material (including mobile forms) increased between May and August in both years. This increase in 'fall out' material was correlated with wrasse abundance at the cliffs (with a one month lag period). The activities of the wrasse on the cliffs (feeding, nest building and territory defence) were considered responsible for the majority of 'fall out' material, with natural mortality and the activity of other large mobile organisms (e.g. crustaceans) also being triplicated. Current flow rate and cliff profile were important in amount of 'fall out' material collected. In low current situations export of fallen material was vertical, while both horizontal and vertical export was associated with moderate to high current environments. Higher 'fall out' was associated with overhanging than vertical cliff surfaces. The 'fall out' of marine organisms in low current situations is likely to provide ail important source of nutrition in close proximity to the cliff, in an otherwise impoverished soft sediment habitat. However, in high current areas material will be exported some distance from the source, with final settlement again occurring in soft sediment habitats (as current speed decreases).

Influence of drought-induced acidification on the mobility of dissolved organic carbon in peat soils

A strong relationship between dissolved organic carbon (DOC) and sulphate (SO42−) dynamics under drought conditions has been revealed from analysis of a 10-year time series (1993–2002). Soil solution from a blanket peat at 10 cm depth and stream water were collected at biweekly and weekly intervals, respectively, by the Environmental Change Network at Moor House-Upper Teesdale National Nature Reserve in the North Pennine uplands of Britain. DOC concentrations in soil solution and stream water were closely coupled, displaying a strong seasonal cycle with lowest concentrations in early spring and highest in late summer/early autumn. Soil solution DOC correlated strongly with seasonal variations in soil temperature at the same depth 4-weeks prior to sampling. Deviation from this relationship was seen, however, in years with significant water table drawdown (>−25 cm), such that DOC concentrations were up to 60% lower than expected. Periods of drought also resulted in the release of SO42−, because of the oxidation of inorganic/organic sulphur stored in the peat, which was accompanied by a decrease in pH and increase in ionic strength. As both pH and ionic strength are known to control the solubility of DOC, inclusion of a function to account for DOC suppression because of drought-induced acidification accounted for more of the variability of DOC in soil solution (R2=0.81) than temperature alone (R2=0.58). This statistical model of peat soil solution DOC at 10 cm depth was extended to reproduce 74% of the variation in stream DOC over this period. Analysis of annual budgets showed that the soil was the main source of SO42− during droughts, while atmospheric deposition was the main source in other years. Mass balance calculations also showed that most of the DOC originated from the peat. The DOC flux was also lower in the drought years of 1994 and 1995, reflecting low DOC concentrations in soil and stream water. The analysis presented in this paper suggests that lower concentrations of DOC in both soil and stream waters during drought years can be explained in terms of drought-induced acidification. As future climate change scenarios suggest an increase in the magnitude and frequency of drought events, these results imply potential for a related increase in DOC suppression by episodic acidification.

Multiple diversity measures to identify complementary conservation areas for the Baja California peninsular cacti

The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km2. Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.

The Limnology of Slapton Ley

Slapton Ley, a freshwater lake, located in south Devon (National Grid Reference SX 825 439), has been the focus of a wide range of research studies since the foundation of the Field Studies Council Centre in Slapton village in 1959, and the creation of the Slapton Ley Nature Reserve. Early concerns over eutrophication of the Lower Ley led to a range of studies focused on the impacts of land use change in the catchment, on nutrient delivery to the Ley, and on interpreting the impact of long-term nutrient enrichment of the Ley from palaeolimnological studies. What has been missing to date, however, is a focused study of the impacts of nutrient enrichment on the chemical and ecological structure and function of the combined Lower and Higher Ley systems. This paper attempts to draw together the various areas of study on the Ley to date in order to provide a review of current understanding of the limnology of Slapton Ley and to identify gaps in our knowledge. The past, present and future trophic status of the Ley is re-interpreted in the light of current understanding of the eutrophication process in the wider scientific community. Recommendations for future research are then made, with a view to the monitoring and management of Slapton Ley and its catchment.

Hydrocarbon biodegradation and soil microbial community response to repeated oil exposure

Bioremediation strategies continue to be developed to mitigate the environmental impact of petroleum hydrocarbon contamination. This study investigated the ability of soil microbiota, adapted by prior exposure, to biodegrade petroleum. Soils from Barrow Is. (W. Australia), a class A nature reserve and home to Australia’s largest onshore oil field, were exposed to Barrow production oil (50 ml/kg soil) and incubated (25 °C) for successive phases of 61 and 100 days. Controls in which oil was not added at Phase I or II were concurrently studied and all treatments were amended with the same levels of additional nutrient and water to promote microbial activity. Prior exposure resulted in accelerated biodegradation of most, but not all, hydrocarbon constituents in the production oil. Molecular biodegradation parameters measured using gas chromatography–mass spectrometry (GC–MS) showed that several aromatic constituents were degraded more slowly with increased oil history. The unique structural response of the soil microbial community was reflected by the response of different phospholipid fatty acid (PLFA) sub-classes (e.g. branched saturated fatty acids of odd or even carbon number) measured using a ratio termed Barrow PLFA ratio (B-PLFAr). The corresponding values of a previously proposed hydrocarbon degrading alteration index showed a negative correlation with hydrocarbon exposure, highlighting the site specificity of PLFA-based ratios and microbial community dynamics. B-PLFAr values increased with each Phase I and II addition of production oil. The different hydrocarbon biodegradation rates and responses of PLFA subclasses to the Barrow production oil probably relate to the relative bioavailability of production oil hydrocarbons. These different effects suggest preferred structural and functional microbial responses to anticipated contaminants may potentially be engineered by controlled pre-exposure to the same or closely related substrates. The bioremediation of soils freshly contaminated with petroleum could benefit from the addition of exhaustively bioremediated soils rich in biota primed for the impacting hydrocarbons.

Sequential hydrocarbon biodegradation of a soil from arid coastal Australia oil-treated under laboratory controlled conditions

A general consistency in the sequential order of petroleum hydrocarbon reduction in previous biodegradation studies has led to the proposal of several molecularly based biodegradation scales. Few studies have investigated the biodegradation susceptibility of petroleum hydrocarbon products in soil media, however, and metabolic preferences can change with habitat type. A laboratory based study comprising gas chromatography–mass spectrometry (GC–MS) analysis of extracts of oil-treated soil samples incubated for up to 161 days was conducted to investigate the biodegradation of crude oil exposed to sandy soils of Barrow Island, home to both a Class ‘‘A” nature reserve and Australia’s largest on-shore oil field. Biodegradation trends of the hydrocarbon-treated soils were largely consistent with previous reports but some unusual behaviour was recognised both between and within hydrocarbon classes. For example, the n-alkanes persisted at trace levels from day 86 to 161 following the removal of typically more stable dimethyl naphthalenes and methyl phenanthrenes. The relative susceptibility to biodegradation of different di- tri- and tetramethylnaphthalene isomers also showed several features distinct from previous reports. The unique biodegradation behaviour of Barrow Is. soil likely reflects difference in microbial functioning with physiochemical variation in the environment. Correlation of molecular parameters, reduction rates of selected alkyl naphthalene isomers and CO2 respiration values with a delayed (61 d) oil-treated soil identified a slowing of biodegradation with microcosm incubation; a reduced function or population of incubated soil flora might also influence the biodegradation patterns observed.

Florística e fitossociologia do estrato arbustivo de área de transição savana-floresta no Parque Estadual de Porto Ferreira, SP

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Avian communities in woodlots in the Parque das Neblinas, Bertioga, São Paulo, Brazil

Parque das Neblinas (PN) is a 2,800 ha nature reserve contiguous with an Atlantic Forest fragment known as Parque Estadual da Serra do Mar located in the municipality of Bertioga, in the state of São Paulo, Brazil. The area originally contained Eucalyptus trees grown for paper pulp production. The aims of the study were the following: (1) to characterize the diversity of the bird community in PN; (2) to compare bird species observed in PN to species found in the Atlantic Forest; and (3) to list the percentages of species endemic to the Atlantic Forest and present in PN. Quantitative surveys used the point count method. The number of avian species recorded in PN totaled 222, of which 150 (66.4%) were associated with forest environments, 66 (29.3%) with open areas, and 10 (4.3%) with aquatic environments. The quantitative survey recorded 141 species and 2,527 contacts in 120 samples for an average of 21.05 contacts per sample. The general diversity index was H´=3.82. The study identified 15 bird species that actively participated in mixed flocks and 25 species endemic to Atlantic Forest, two of which present some kind of concern relating to conservation. Areas with Eucalyptus trees and a dense understory displayed the greatest bird species diversity, as opposed to areas with less developed or non-existent understories.

Home range, movements and diurnal roosts of the endangered thin-spined porcupine, Chaetomys subspinosus (Rodentia: Erethizontidae), in the Brazilian Atlantic Forest

Chaetomys subspinosus is the sole species within the Chaetomyinae subfamily of Caviomorph rodents. This poorly studied porcupine is restricted to the Atlantic Forest in eastern Brazil, where deforestation and habitat fragmentation threaten its survival. Data on the ranging and roosting behavior of C. subspinosus is fairly scarce as it is difficult to observe these behaviors in nature and, consequently, it is very rarely detected during field surveys. We monitored the home ranges of three radio-tagged females over the course of 1 year (2005-2006) and collected data on several aspects of their natural history including movement patterns and the use of diurnal roosts and latrines. The animals were monitored at Parque Estadual Paulo Cesar Vinha, a nature reserve dominated by restinga forests, a subtype of Atlantic Forest occurring on sandy soil. The estimated home range varied little between individuals and was relatively small (mean = 2.14 ha/individual and 1.09 ha/individual using minimum convex polygon and kernel methods, respectively). The animals travelled an average of 147 m/night (range: 21-324 m/night) between two consecutive day roosts. The day roosts were mostly located on vine and liana tangles in the canopy which also aid in connecting the canopy to adjacent trees or the forest floor. Latrines were mostly located near the ground in places heavily protected by spiny bromeliads or by other tangled vegetation. Our data suggests that C. subspinosus has the smallest range among all Neotropical Erethizontids which is likely due to its small size and strictly folivorous diet. Our data also helps explain why C. subspinosus is so difficult to observe in nature: researchers should focus on arboreal masses of tangled vegetation where individuals will normally rest during the day. (C) 2011 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.

Population size of threatened and endemic birds of the Cerrado in Estacao Ecologica de Itirapina, a fragmented area in the State of Sao Paulo, Brazil

The pressures for land use change have led to an increasing isolation of habitat remnants throughout the world. The goal of this study was to estimate the population size and density of some endemic and threatened species in a nature reserve in the Cerrado biome. One hundred and thirty four point transects were undertaken at the Estacao Ecologica de Itirapina (EEI), one of the last natural grassland savannah remnants in Sao Paulo state, in the south-east of Brazil between September and December 2006 and densities estimated for seven species (four endemic to the Cerrado, one near-endemic and two grassland specialists). Neither species reached the minimum viable population size of 500-5000 individuals. Four species, White-banded Tanager, White-rumped Tanager, Black-throated Saltator and Sharp-tailed Tyrant have populations ranging from 112 to 248 individuals, while the other species have a low population (< 60 individuals). The mean densities of Sharp-tailed Tyrant and Cock-tailed Tyrant in the EEI grassland showed similar values to those observed in larger areas of the Cerrado, which may indicate that the EEL grassland area is well conserved. In spite of the restricted size of the EEI, small areas can maintain some endemic and threatened bird populations, thus contributing to local biodiversity and the ecological processes in the region. The capacity of fragments of Cerrado (similar to 2,000 ha) to maintain populations of endemic and threatened bird species is unlikely to be effective in the long term.

The First Density Estimation of an Isolated Eurasian Lynx Population in Southwest Asia

During November 2010–February 2011, we used camera traps to estimate the population density of Eurasian lynx Lynx lynx in Ciglikara Nature Reserve, Turkey, an isolated population in southwest Asia. Lynx density was calculated through spatial capture—recapture models. In a sampling eff ort of 1093 camera trap days, we identifi ed 15 independent individuals and estimated a density of 4.20 independent lynx per 100 km2, an unreported high density for this species. Camera trap results also indicated that the lynx is likely to be preying on brown hare Lepus europaeus, which accounted for 63% of the non-target species pictured. As lagomorph populations tend to fl uctuate, the high lynx density recorded in Ciglikara may be temporary and may decline with prey fl uctuation. Therefore we recommend to survey other protected areas in southwestern Turkey where lynx is known or assumed to exist, and continuously monitor the lynx populations with reliable methods in order to understand the populations structure and dynamics, defi ne sensible measures and management plans to conserve this important species.

Pollen analysis of a peat profile from the Rieseberger Moor, Lower Saxony, Germany

The Rieseberger Moor is a fen, 145 hectares in size, situated about 20 km east of Brunswick (Braunschweig), Lower Saxony, Germany. Peat was dug in the fen - with changing intensity - since the mid-18th century until around AD 1955. According to Schneekloth & Schneider (1971) the remaining peat (fen and wood peat) is predominantly 1.5 to 2 m thick (maximum 2.7 m). Part of the fen - now a nature reserve (NSG BR 005) - is wooded (Betula, Salix, Alnus). For more information on the Rieseberger Moor see http://de.wikipedia.org/wiki/Rieseberger_Moor. Willi Selle was the first to publish pollen diagrams from this site (Selle 1935, profiles Rieseberger Torfmoor I and II). This report deals with a 2.2 m long profile from the wooded south-eastern part of the fen consisting of strongly decomposed fen peat taken A.D. 1965 and studied by pollen analysis in the same year. The peat below 1.45 m contained silt and clay, samples 1.48 and 1.58 m even fine sand. These samples had to be treated with HF (hydrofluoric acid) in addition to the treatment with hot caustic potash solution. The coring ended in sandy material. The new pollen data reflect the early part of the known postglacial development of the vegetation of this area: the change from a birch dominated forest to a pine forest and the later spreading of Corylus and of the thermophilous deciduous tree genera Quercus, Ulmus, Tilia and Fraxinus followed by the expansion of Alnus. The new data are in agreement with Selle's results, except for Alnus, which in Selle's pollen diagram II shows high values (up to 42% of the arboreal pollen sum) even in samples deposited before Corylus and Quercus started to spread. On contrary the new pollen diagram shows that alder pollen - although present in all samples - is frequent in the three youngest pollen spectra only. A period with dominating Alnus as seen in the uppermost part of Selle's pollen diagrams is missing. The latter is most likely the result of peat cutting at the later coring site, whereas the early, unusually high alder values of Selle's pollen study are probably caused by contamination of the pollen samples with younger peat. Selle took peat samples usually with a "Torfbohrer" (= Hiller sampler). This side-filling type of sampler with an inner chamber and an outer loose jacket offers - if not handled with appropriate care - ample opportunities to contaminate older peat with carried off younger material. Pollen grains of Fagus (2 % of the arboreal pollen sum) were found in two samples only, namely in the uppermost samples of the new profile (0.18 m) and of Selle's profile I (0.25 m). If this pollen is autochthonous, with other words: if this surface-near peat was not disturbed by human activities, the Fagus pollen indicates an Early Subboreal age of this part of the profile. The accumulation of the Rieseberg peat started during the Preboreal. Increased values of Corylus, Quercus and Ulmus indicate that sample 0.78 m of the new profile is the oldest Boreal sample. The high Alnus values prove the Atlantic age of the younger peat. Whether Early Subboreal peat exists at the site is questionable, but evidently none of the three profiles reaches to Late Subboreal time, when Fagus spread in the region. Did peat-growth end during the Subboreal? Did younger peat exist, but got lost by peat cutting or has younger peat simply not yet been found in the Rieseberg fen? These questions cannot be answered with this study. The temporary decline of the curve of Pinus for the benefit of Betula during the Preboreal, unusual for this period, is contemporaneous with the deposition of sand (Rieseberger Moor II, 1.33 - 1,41 m; samples 1.48 and 1.58 m of the new profile) and must be considered a local phenomenon. Literature: Schneekloth, Heinrich & Schneider, Siegfried (1971). Die Moore in Niedersachsen. 2. Teil. Bereich des Blattes Braunschweig der Geologischen Karte der Bundesrepublik Deutschland (1:200000). - Schriften der wirtschaftswissenschaftlichen Gesellschaft zum Studium Niedersachsens e.V. Reihe A I., Band 96, Heft 2, 83 Seiten, Göttingen. Selle, Willi (1935) Das Torfmoor bei Rieseberg. - Jahresbericht des Vereins für Naturwissenschaft zu Braunschweig, 23, 46-58, Braunschweig.

Natural production of Tuber aestivum in central Spain: Pinus spp. versus Quercus spp. brûles

Aim of study: Tuber aestivum is the most widespread edible truffle, with increasing commercial interest. This species can produce carpophores with conifer hosts, in contrast with the inability of Pinus spp. to induce fruiting in other truffle species such as Tuber melanosporum. Therefore the objective is to compare the characteristics and carpophore production of T. aestivum brûlés associated with Pinus spp. versus Quercus spp. Area of study: We studied the natural habitats of T. aestivum in the Alto Tajo Nature Reserve in central Spain. Material and methods: During 5 years, we monitored the production of carpophores and brûlé size of 145 T. aestivum brûlés associated with Pinus nigra subsp. salzmanni and P. sylvestris and Quercus ilex subsp. ballota and Q. faginea hosts. Statistical treatment was performed using the Statistica Program v. 6. Main results: The size of brûlés associated with Pinus was significantly smaller than that of brûlés associated with Quercus. However, carpophore production per brûlé, and especially for brûlés of similar size, was greater when the host plant was a pine. After accounting for brûlé size, the production of brûlés associated with Pinus spp. was 2.23 (95% CI, between 1.35 and 3.69) and 1.61 (95% CI, between 1.02 and 2.54) times greater than the production of brûlés associated with Quercus faginea and Q. ilex subsp. ballota, respectively. Research highlights: The considerable ability of Pinus nigra subsp. salzmanni and P. sylvestris to form effective brûlés and to produce carpophores of Tuber aestivum in natural conditions was clearly demonstrated, and suggest that those species can be of use in the culture of T. aestivum.